. >> the united states government had nothing to do with this video. we absolutely reject its content and message. >> reporter: so far, more than 200 people have been hurt in protests at 11 u.s. compounds, four killed in libya earlier this week. the protesters are a mix of islamic hard liners and huligans. christopher stevens was killed as protesters attacked on tuesday. also killed, sean smith and two former navy s.e.a.l.s working as contractors. stevens sister, hillary. >> he's been in these countries so long, i haven't reflected about how dangerous the work he was doing was. >> reporter: in lebanon, pakistan, sudan and jordan, more anti-american protests. in yemen thursday, protesters broke into the embassy parking lot smashing windows. the fbi is working overseas and here at home investigating the man who posted the film online. he was on probation and not supposed to be on the internet. now, they are warning that extremist groups could act stateside. they haven't mentioned any specific threats but warn first responders here of the potential for pr